Is there a way to copy UVs between maps on the same object, or merge maps into one?
You can copy UV maps from one object to another (provided their vertex count and index match) by selecting one object, then shift+select the second.

I press spacebar - type in "UV" and select "Transfer UV Maps".

I'm not sure but I think the order is copy from object 1 to active object. You may have to experiment to find out the correct selection order (use UNDO). It will copy to the currently selected UV map in the "Object data" tab.